Vacuum cleaners that employ a cyclonic cleaning system, such as upright and canister vacuum cleaners, stick vacuums, central vacuums etc. are common on the market today. Dust from the dust laden airstream which is sucked into the vacuum cleaner is separated in a dust separation chamber and collected in a dustbin, which must be frequently emptied by the user. As long as the dust level in the dustbin is below a critical level, normal functionality of the dust separation in the vacuum cleaner is provided.
However, a common problem for vacuum cleaners with a separate dustbin is that the user forgets to empty the dustbin before the critical level is reached, which results in unnecessary clogging of filters and other parts of the vacuum cleaner. The consequences of this are loss of cleaning performance and increased amount of maintenance of e.g. the main filter and filter screen. Thus, there is a need for indicating to the user when it is time to empty the dustbin before the critical level is reached.
It is known to arrange optical dust indicators in vacuum cleaners for the purpose of detecting dust. The optical dust indicators are typically based on optical sensors providing a detection system, such as a light emitter in combination with a light receiver, which are arranged such that when dust is present in the optical path of the light signal provided by the light emitter, the light receiver detects a decreased or blocked light signal. The optical dust indicators are sensitive to dust getting stuck somewhere in the optical path of the detection system, as this blocks the light signal.